[net-next,v6,08/14] net/smc: Introduce generic netlink interface for diagnostic purposes

Commit Message

Karsten Graul Nov. 26, 2020, 8:39 p.m. UTC

From: Guvenc Gulce <[e-mail]>

Introduce generic netlink interface infrastructure to expose
the diagnostic information regarding smc linkgroups, links and devices.

Signed-off-by: Guvenc Gulce <[e-mail]>
Signed-off-by: Karsten Graul <[e-mail]>
---
 include/uapi/linux/smc.h | 11 ++++++++++
 net/smc/Makefile         |  2 +-
 net/smc/af_smc.c         | 10 ++++++++-
 net/smc/smc_netlink.c    | 46 ++++++++++++++++++++++++++++++++++++++++
 net/smc/smc_netlink.h    | 23 ++++++++++++++++++++
 5 files changed, 90 insertions(+), 2 deletions(-)
 create mode 100644 net/smc/smc_netlink.c
 create mode 100644 net/smc/smc_netlink.h

Comments

Jakub Kicinski Nov. 28, 2020, 9:06 p.m. UTC | #1

On Thu, 26 Nov 2020 21:39:10 +0100 Karsten Graul wrote:
> +/* SMC_GENL family definition */
> +struct genl_family smc_gen_nl_family __ro_after_init = {
> +	.hdrsize = 0,
> +	.name = SMC_GENL_FAMILY_NAME,
> +	.version = SMC_GENL_FAMILY_VERSION,
> +	.maxattr = SMC_GEN_MAX,
> +	.netnsok = true,
> +	.module = THIS_MODULE,
> +	.ops = smc_gen_nl_ops,
> +	.n_ops =  ARRAY_SIZE(smc_gen_nl_ops)
> +};

Sorry, one more spin.

Now you'll let any attribute in. We try to reject any input that won't
be acted on in the kernel these days to allow the interfaces to be
extended in the future without worrying that something that was
throwing random data in the messages will suddenly start misbehaving.

You should still declare a policy just make it empty. And you can make
the policy array size 1, and set .maxattr to 1, AFAIK. These are both
pretty much* for input validation only.

* the only exception is dumping the policy to be able to tell types in
  user space automatically, but I don't think you'll care.

Patch

diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
index 0e11ca421ca4..b604d64542e8 100644
--- a/include/uapi/linux/smc.h
+++ b/include/uapi/linux/smc.h
@@ -33,4 +33,15 @@  enum {				/* SMC PNET Table commands */
 #define SMCR_GENL_FAMILY_NAME		"SMC_PNETID"
 #define SMCR_GENL_FAMILY_VERSION	1
 
+/* gennetlink interface to access non-socket information from SMC module */
+#define SMC_GENL_FAMILY_NAME		"SMC_GEN_NETLINK"
+#define SMC_GENL_FAMILY_VERSION		1
+
+/* SMC_GENL_FAMILY top level attributes */
+enum {
+	SMC_GEN_UNSPEC,
+	__SMC_GEN_MAX,
+	SMC_GEN_MAX = __SMC_GEN_MAX - 1
+};
+
 #endif /* _UAPI_LINUX_SMC_H */
diff --git a/net/smc/Makefile b/net/smc/Makefile
index cb1254541f37..77e54fe42b1c 100644
--- a/net/smc/Makefile
+++ b/net/smc/Makefile
@@ -2,4 +2,4 @@ 
 obj-$(CONFIG_SMC)	+= smc.o
 obj-$(CONFIG_SMC_DIAG)	+= smc_diag.o
 smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o smc_llc.o
-smc-y += smc_cdc.o smc_tx.o smc_rx.o smc_close.o smc_ism.o
+smc-y += smc_cdc.o smc_tx.o smc_rx.o smc_close.o smc_ism.o smc_netlink.o
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index f79b59a972f0..47340b3b514f 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -45,6 +45,7 @@ 
 #include "smc_ib.h"
 #include "smc_ism.h"
 #include "smc_pnet.h"
+#include "smc_netlink.h"
 #include "smc_tx.h"
 #include "smc_rx.h"
 #include "smc_close.h"
@@ -2495,10 +2496,14 @@  static int __init smc_init(void)
 	smc_ism_init();
 	smc_clc_init();
 
-	rc = smc_pnet_init();
+	rc = smc_nl_init();
 	if (rc)
 		goto out_pernet_subsys;
 
+	rc = smc_pnet_init();
+	if (rc)
+		goto out_nl;
+
 	rc = -ENOMEM;
 	smc_hs_wq = alloc_workqueue("smc_hs_wq", 0, 0);
 	if (!smc_hs_wq)
@@ -2569,6 +2574,8 @@  static int __init smc_init(void)
 	destroy_workqueue(smc_hs_wq);
 out_pnet:
 	smc_pnet_exit();
+out_nl:
+	smc_nl_exit();
 out_pernet_subsys:
 	unregister_pernet_subsys(&smc_net_ops);
 
@@ -2586,6 +2593,7 @@  static void __exit smc_exit(void)
 	proto_unregister(&smc_proto6);
 	proto_unregister(&smc_proto);
 	smc_pnet_exit();
+	smc_nl_exit();
 	unregister_pernet_subsys(&smc_net_ops);
 	rcu_barrier();
 }
diff --git a/net/smc/smc_netlink.c b/net/smc/smc_netlink.c
new file mode 100644
index 000000000000..e9a56148e71b
--- /dev/null
+++ b/net/smc/smc_netlink.c
@@ -0,0 +1,46 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  Generic netlink support functions to interact with SMC module
+ *
+ *  Copyright IBM Corp. 2020
+ *
+ *  Author(s):	Guvenc Gulce <[e-mail]>
+ */
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/if.h>
+#include <linux/smc.h>
+
+#include "smc_core.h"
+#include "smc_netlink.h"
+
+/* SMC_GENL generic netlink operation definition */
+static const struct genl_ops smc_gen_nl_ops[] = {
+};
+
+/* SMC_GENL family definition */
+struct genl_family smc_gen_nl_family __ro_after_init = {
+	.hdrsize = 0,
+	.name = SMC_GENL_FAMILY_NAME,
+	.version = SMC_GENL_FAMILY_VERSION,
+	.maxattr = SMC_GEN_MAX,
+	.netnsok = true,
+	.module = THIS_MODULE,
+	.ops = smc_gen_nl_ops,
+	.n_ops =  ARRAY_SIZE(smc_gen_nl_ops)
+};
+
+int __init smc_nl_init(void)
+{
+	return genl_register_family(&smc_gen_nl_family);
+}
+
+void smc_nl_exit(void)
+{
+	genl_unregister_family(&smc_gen_nl_family);
+}
diff --git a/net/smc/smc_netlink.h b/net/smc/smc_netlink.h
new file mode 100644
index 000000000000..0c757232c0d0
--- /dev/null
+++ b/net/smc/smc_netlink.h
@@ -0,0 +1,23 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  SMC Generic netlink operations
+ *
+ *  Copyright IBM Corp. 2020
+ *
+ *  Author(s):	Guvenc Gulce <[e-mail]>
+ */
+
+#ifndef _SMC_NETLINK_H
+#define _SMC_NETLINK_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+extern struct genl_family smc_gen_nl_family;
+
+int smc_nl_init(void) __init;
+void smc_nl_exit(void);
+
+#endif